


Object of Curiosity

by orphan_account



Category: Fire Emblem: Fuukasetsugetsu | Fire Emblem: Three Houses
Genre: Alternate Universe - Modern Setting, Felix Fraldarius Cannot Swim, Human/Monster Romance, M/M, Masturbation, Merman!Sylvain Jose Gautier, Pet Names, Praise Kink, Size Difference, Size Kink, Written for Mermay 2020, slight blood kink
Language: English
Status: Completed
Published: 2020-06-01
Updated: 2020-09-23
Packaged: 2021-03-02 20:35:00
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 3
Words: 7,909
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/24482866
Author URL: https://archiveofourown.org/users/orphan_account/pseuds/orphan_account
Summary: One clawed hand emerged to grip at the thick wood, orange points driving deep, and then another, and up rose the mermaid to lean on its arms at the end of the pier- Felix felt a hot flash of something that was most certainly not dread spike through him.“Aw,” its voice was strange and lilting and deeper than Felix remembered, “Don’t be afraid. I only bite sometimes.” It rested its chin in its palm, odd amber eyes flashing dangerously. It smiled down at Felix. “You can call me Sylvain.”Felix enters a bargain.
Relationships: Felix Hugo Fraldarius/Sylvain Jose Gautier
Comments: 5
Kudos: 175





	1. Chapter 1

**Author's Note:**

> hello hello! this is yet another work inspired by the wonderful [casey](https://twitter.com/eggyankee) on twitter, particularly [this tweet](https://twitter.com/eggyankee/status/1258850886136336386?s=21). enjoy!

It wasn’t as if Felix had jumped off the cliff and into the sea because he’d wanted to. He had bitten off more than he could chew in… well, it didn’t matter much what’d landed him in the water. The fall had been too careless, Felix over-rotated in midair, his upper back smashed against the churning waves instead of his feet. He couldn’t move. Paralyzed, he was sinking fast- his lithe, compact frame did not lend itself to buoyancy, and he watched, helpless, as the greenish light of hope slipped further and further from him. He’d really done it this time, Felix thought, having flung himself from one mortal danger into another. These waters were infested with mermaids. Mermaids, protectors of the sea. Big, dangerous. Deadly. He needed to get out of there, and fast- if he didn’t die by drowning, he’d be skewered on a claw, sliced up by razor-sharp fins, turned into fish food by rows and rows of jagged teeth, or any number of horrible things. The light was getting smaller. His air was running out.

“You’ve drifted pretty deep for a human who can barely swim, haven’t you?”

Fuck. He’d overstayed his welcome.

A giant, clawed hand shot out of the dark. Points drove painfully into his torso, but not hard enough to draw blood. A warning. Narrow, bioluminescent eyes with vertical pupils opened and a threatening, toothy smile came into Felix’s view. Red hair floated around the pale face in a bloody halo. Felix tensed. His body was on pins and needles and hurt like hell.

“Hm. You’re a pretty one, aren’t you? Shame you went too far down.” The claws around his stomach slackened, one point trailing up to underneath his chin, tilting his head back, observing. His pulse thundered just underneath the deadly point. Felix got a look at the body of his captor as it circled him- a powerful, muscled torso and a shark’s tail that matched its hair, covered completely in razor-edged scales. Scars covered the body from top to bottom, each one telling of a battle lived and won. Felix’s lungs _burned_. Black spots began to mar his vision. Every cell in his body told him to swim, that if he could just break the surface he’d be fine, be safe, that mermaids can’t risk beaching themselves, but he kept his body still. In the back of his fading mind, he hoped that he seemed respectful in his stillness, but really he’d rather just drown the old-fashioned way than live through becoming piecemeal.

“You aren’t trying to escape. I like that.” It said, brushing bubbles through Felix’s hair and over his skin. It brought its free claw to its chin. The one resting in the soft spot underneath Felix’s jaw cupped his face, large enough to curl around his skull. Tiny, iridescent scales bit into his cheeks. “Tell you what, I’ll make you a deal. You’re pretty, and you’re smart. I’ll bring you back to the top,” Reality was slipping, “but for a price. How does that sound?” Felix saw the bubbles come from his mouth, heard himself make a noise, felt himself being pulled towards the surface.

He wasn’t awake to remember the bitten-off claw shoved not quite carelessly down his throat to force the water from his stomach and out from his lungs, nor the way he was dragged by his limp wrists through the sea. It was by force of luck, or perhaps fate, that he was dumped on his own pier among deep, fresh cuts in the wood from where his captor had pulled itself up before lifting Felix the way one might lift an article of clothing that had mistakenly fallen into a tub. It was there, underneath the fading summer sun with the depths licking at his ankles that he came to; cold, alone, and worse for the wear.

Felix forced his eyes to open through the sticky saltwater crust that glued them together and coughed like hell. His throat felt like it was lined with sandpaper, and when he wiped his mouth on the back of his hand there was blood among the spit. God, he felt _awful_ . Everything ached, he could feel bruises beginning to bloom on his shoulder, his wrists. One or two were bound to show up where that mermaid’s claws had dug into him. He sat there, on the edge of the pier, wondering dully what Glenn would say if he saw him now, wet and wounded and freshly indebted to some sea monster, or worse yet, what their old man would say. _It’s no wonder your red string goes down to the bottom of the sea._ Laughed Glenn in his mind’s eye, mocking him from his place to the right of their father, across the dark dining table. _You always did sink like a rock._ Felix sucked in a long breath, pulling himself out from his head. Glenn wasn’t there, neither was Rodrigue. He was alone among the sea and the sky, and, it occurred to him, he was bleeding. A litany of tiny cuts littered his forearms from where he’d been pulled along by the mermaid, each oozing sluggishly, like they weren’t sure how they got to be there either. He watched, for a moment, the red roll down his arms, joining together like raindrops on a window and falling off the tips of his fingers where they gripped the end of the pier, down into the deep green waves. He hastily rinsed his arms in the sea, grit his teeth against the sting, and hauled himself back towards home.

It was in the shower, after a thorough scrub under scalding water that left him pink and raw and a significant amount of time spent removing stray scales from his arms, that he noticed the little loop of braided red wound tight around his left wrist. He’d watched, blank and unseeing, as blood and salt swirled down the drain in a sorrowful pinwheel, expecting it to wash away as well, but it stayed quite put. Felix felt his stomach drop. He groaned and pressed his forehead to the cool tile, wet hair stuck to his face and neck, miserable. _Nice going._ He’d entered into a contract with a mermaid. He’d agreed to be saved for a price, but… he had no idea what his end of the bargain was. He slipped a finger underneath the marker. It was smooth, silky- and not going anywhere; he had to press hard into the soft underside of his wrist to get beneath it. He stared. It begged a question he did not want to answer. Deep down in his heart of hearts, he had called out to that creature, begged it to save him. Felix blinked. The water was starting to run cold. He turned off the tap, and let the question wash away with the last of the suds.

A week came and went. He’d scoured literature of all kinds in an effort to find anything about his predicament, even going so far as to venture into Glenn’s old room (a dusty trove of maritime myths and legends), but to no avail; everything had either been the kinds of things he was familiar with, like tales of otherworldly beauty luring sailors to their deaths, or histories of other mer-denominations, like sirens and selkies and so on. There was no mention of contracts aside from warnings. _Beware the fool who sold himself to the deep,_ read a footnote in the oldest bestiary he could find, _for he who could not find himself on land is blind to his uselessness within the sea._ Felix abandoned his plot of snipping the cord.

The first time he wandered out to the end of the pier, there was nothing. The stars twinkled above him, waves sloshing gently against the wood. He’d traced the claw marks left where he sat, plucking out scales wedged within the grain much the way he’d plucked bloodied ones from his arms. They were tiny little things, barely the size of his pinky-nail, translucent save for a wonderful iridescent sheen that made itself known under the moonlight. There were plenty of them, enough for a small handful that looked like he was holding a galaxy. Felix kicked his feet back and forth, bumping his heels against where the wood met the water. _How could something so beautiful come from something so dangerous?_ As tiny as they were, each scale had a cutting edge. They stuck to his hands when he piled them to his side. He shifted, bumping around the back of the wooden support. A sharp pain zipped through him- he cursed, and pulled his leg up to see a long, shallow slice across the top of his right foot. It stung where the seawater seeped into the split. Indignant, he stuck his hand into the water, feeling around because _what the hell was that_ , and pulled up another, much bigger, scale. Even broken as it was, it spanned the width of his palm with a razor’s edge, gleaming an orangey gold under the moonlight. A gust of wind carried the pile of tiny scales back into the water. Felix made his way back home, careful not to slice his fingers as he turned the sharp, shiny thing over and over in his hand. The underside of it was milky white.

There were three more evenings spent picking iridescent scales from the grain of the wood before their cause came around. Each time, Felix would sit, trace the claw marks etched in the wood, turn the red band around and around on his wrist. And so, he was doing just that, feet dangling in the water and staring out at the gently rolling sea, green and glittering, when two odd, unmistakable eyes stared back. Felix bristled, jumping up as dread settled itself quite nicely in the pit of his stomach. It would suffice to say that in the time since… selling his soul, or whatever it was he had done, he’d managed to cultivate a good bit of anxiety towards anything that lived in the ocean. One clawed hand emerged to grip at the thick wood, orange points driving deep, and then another, and up rose the mermaid to lean on its arms at the end of the pier- Felix felt a hot flash of something that was most certainly not dread spike through him.

“Aw,” its voice was strange and lilting and deeper than Felix remembered, “Don’t be afraid. I only bite sometimes.” It rested its chin in its palm, odd amber eyes flashing dangerously. It smiled down at Felix. “You can call me Sylvain.” Felix found himself rooted to the spot. Sylvain was _huge_. Even just from the waist up, he towered over Felix, casting a shadow over him and blotting out the sun. His hair was the same reddish orange as the scale Felix pulled from the wood. The finned tips of his ears poked out on the side of his head, adorned with a number of little golden hoops- _victory prizes,_ Felix realized. Twin sets of gills contoured along his neck fluttered when he breathed, and they led Felix’s eyes to trace over Sylvain’s defined chest and stomach, flickering along a scar that stretched from the top of his shoulder down to his waist where rough skin melted seamlessly into liquid muscle and the tops of gleaming orange scales disappeared into the sea. He looked back up to Sylvain’s eyes, to the ( _perfect,_ he thought, and then remembered that if he made one wrong move he’d be on the sharp end of a claw) smile that hid sharp, sharp teeth. Sylvain was inarguably beautiful, and _dangerous,_ and Felix found himself empathizing with those poor sailors he’d read so much about. “Well? It’s only polite to tell someone your name once they’ve told you theirs.” Said Sylvain, moving to beckon Felix forward, “You could certainly talk before. I’d hate to have to force it from you.” The wood creaked under his weight.

“Felix.” His voice sounded foreign to him. “My name is Felix.” Sylvain looked at him like he was prey, and Felix had a feeling that look would be haunting his nights for quite some time- if he ever made it home, that is. He felt himself take a step forward. Sylvain hummed.

“Felix,” He said, testing the name out, rolling it around on his tongue like it was something to be savored, sending a shiver down Felix’s spine. “Felix, Felix. I like that.” He reached forwards, taking hold of Felix’s chin, tilting his head this way and that. “A pretty name for a pretty boy. I’m so glad I remembered correctly,” Felix could see the webbing between his fingers, where it turned from skin to scale, felt a point pinch into his cheek. Sylvain’s smile dropped. “Otherwise I’m not sure what I’d have done.” He traced down Felix’s neck, leaving a trail of fire behind as he made his way to his wrist, where the braided scarlet sat. He could feel his heart pounding. “I bet you’d like to discuss this, wouldn’t you?” Felix nodded, stiff and awkward, and Sylvain smiled again, softer this time. “Come, sit.” _Sit where?_ Felix, for his single step forward before, couldn’t get his feet to move. “Don’t be shy,” Sylvain taunted, and when Felix still didn’t budge, he was swept up into the air as Sylvain pushed off from the pier, landing him on his stomach as he swam off. Felix was now completely at his mercy. He squeezed his legs around Sylvain’s thick, sturdy torso, hands coming to land on his chest; he could feel every little movement as it rolled through Sylvain, and he’d be lying if it didn’t set an embarrassing warmth floating through him. The tips of his ears burned. The skin of Sylvain’s upper body was rough, like he was holding on to a fine-grit sandpaper, and cool to the touch. It rubbed against his thighs where his shorts had ridden up. They stayed like that for what felt to Felix like hours, just floating in circles, not all too far from the pier, making lazy figure eights in the water; Sylvain, watching Felix, skittish and stranded between the deep sea and the open sky, and Felix trying desperately to keep his cool, strung between his shorts climbing ever higher and the imminent threat of Sylvain. Sylvain’s motions were smooth and repetitive. He never made an attempt to do anything sudden, to take Felix down to the ocean floor or run him through with a claw or bite his head off or any number of terrible things Felix thought he might. 

“Why are you doing this?” Felix eventually muttered, more to the air above Sylvain’s clavicle than anything else. Sylvain made a noncommittal _hm?_ , slowly stretching his arms above his head. The action rippled through him, rippling twofold through Felix. _Does he think I’m an idiot?_ Felix groused to himself. “Why are we just swimming in circles? Don’t you want to… I don’t know,” he shifted nervously, “Want to take my soul, or something?” It sounded particularly dumb said out loud. _Maybe I am an idiot._ Sylvain stopped moving, staring openly at him. He could see his reflection in those molten amber eyes. Felix squirmed. He felt stripped bare by that gaze, like with each passing second a layer of his identity peeled off and into the water, like he was an open book waiting to be read. Felix stared back, not quite defiantly. Sylvain tipped his head back into the water, and started… _shaking?_ He was trembling, from his chest all the way down, bringing his hands up to his face and oh _god,_ Felix was really in for it now, he’d angered a mermaid and he didn’t even have a will- Sylvain’s head popped back up, teeth bared, hands dragging down his face and making this _sound_ \- oh. Sylvain was laughing. He was laughing so hard, in fact, that his whole body convulsed and sent Felix tumbling forwards, flat against Sylvain’s chest. His face burned. “Don’t _laugh_ ,” he yelled, “you’re the one who pulled me up!” But Sylvain kept laughing, deep and full, coming to rest his hands against Felix’s sides to guide him back up. Felix did not think about how each hand was probably large enough for him to be able to sit comfortably in it.

“Take your soul,” Sylvain said, still laughing, “That’s one I haven’t heard in a long, long time. No, Felix, I’m not going to _take your soul._ Do you know anything about how this works?” Felix shook his head, cheeks yet aflame. “Well, to start, I took you out so you’d stop being so _scared_ . It’s no good trying to set terms with someone terrified unless you want to just bend them to your will. Not that I haven’t done that before,” _Um,_ thought Felix, tensing up again, “but that’s not needed.” Sylvain finished. He took Felix’s left wrist in his hand, thumb running across the little braided band, careful not to catch the wrong side of his scales against the skin there. “You’re so skittish, like a little kitten.” Felix felt the pet name crash over him, impressively going even redder. He looked like he had a sunburn all over his face and all down his neck. A mischievous smile crept onto Sylvain’s face as he narrowed his eyes, and Felix really did _not_ need the reminder that he was still technically in peril, nor did he need his awful mind to immediately start wondering about what kind of bite marks those teeth would leave. Sylvain dropped his arm back down into the water. “Oh? You like that, do you, kitten?” Felix pressed his hands down in front of where he was seated. The effects hearing Sylvain call him _kitten_ had on his body were drastic and immediate. “Very interesting. Well, I won’t be taking your soul, or stealing your eyes, or cursing you to silence, or anything of the sort. Think of this as more of a… gentleman’s agreement. The only thing is,” A point came to rest underneath Felix’s jaw, teasing, pressing just so, “I haven’t figured out what I want my end of the bargain to be, so I guess you’ll just have to keep seeing me until I decide.” Felix hadn’t noticed that Sylvain had guided them back towards the pier until he felt the rough wood bump against his back. Sylvain plucked Felix off his stomach, sitting him among the claw marks and hauling himself up onto his elbows. He took Felix’s wrist again, thumbing at the braid. “Keep this for now,” Sylvain said, letting it go in favor of holding Felix’s face, ghosting his thumb over Felix’s bottom lip, watching intently as it bounced. A scale caught. He smeared the drop of blood that pooled there, and Felix watched, transfixed, as he took the bloodied claw into his mouth, smiling around it. “I’ll come when you need me, kitten. Until next time.”

And like that, the sun was low in the sky and Felix was back where he started, with nothing but a bloody lip and too-tight shorts to show for it.

Perhaps it was a blessing in disguise that, upon returning to his room, Felix was a bit preoccupied and did not dwell on the events of that afternoon. He’d been frightfully hard ever since he’d been called _kitten_ the first time, and the thought of it made him go embarrassingly hot all over. His thighs were raw where they’d rubbed against Sylvain’s skin, the little bit of a burn as he peeled his shorts off sent sparks dancing deliciously up his spine. He made his way to the bed, with barely the presence of mind to spit in his palm before taking his cock in his fist; Sylvain was just so _big,_ so _dangerous_ . He could probably, definitely, easily split Felix in two. God, if he blunted the point of one of those claws- he ran his thumb over the head, leaking freely, shivering at the slick slide- just one would fill him up and stretch him wider than his hands could ever hope to. He brought his free hand to his mouth (he was really going all in, wasn’t he,) and slid his fingers against his tongue; they tasted like he’d imagine Sylvain would, like salt and sweat and _oh_ , the tang of copper filled his mouth where the split on his lip opened back up. He moaned, loud and open around himself, letting his hand fall away, smearing spit and blood across his cheek. _That’s right, kitten_ , he imagined Sylvain would say into his ear with that deep, strange voice of his, opening him up. He’d be so _big_ under Felix, his thighs would start to ache from being spread so wide and oh, _god_ , the way Sylvain’s skin would drag over him, just this side of too much and yet not enough- he slid his hand over his cock the way he’d want Sylvain to slide in and out of him, _so tight, so good for me._ Or, maybe, he’d get opened up with Sylvain’s tongue- he’d only seen it for a split second, hidden away in that perfect mouth, but Felix’s imagination was already running wild- smooth and wet and so, so deep. He pumped his cock fast and hard, copper from his split lip filling his mouth as he bit it, racing towards the precipice and thinking of the sweet, sweet stretch that would stuff him so full he’d be shaking like a leaf, moaning and drooling and unable to say anything except _Sylvain, Sylvain, Sylvain_ . He pressed into his thigh. The pain that lanced through him pushed him over the edge and he came all over himself, back arched and Sylvain’s name on his lips. He flopped on the bed, breathing hard, staring at the ceiling fan as it idly turned around and around. _At least my doom is sexy,_ he thought dully. He set about cleaning himself up, and turned bright pink when he saw a telltale splotch of white on the red of the braid around his wrist.


	2. Chapter 2

**Notes for the Chapter:**

> there's some description of sylvain as wounded here, so if blood isnt ur thing, ur welcome to skip to ch3. this is all just plot and worldbuilding next ch is where the porn is :)

They kept meeting again after that. Felix would make his way to the end of the pier in the early afternoon, before the sun-bleached wood became too hot underneath his bare feet, and Sylvain would appear in the minutes following. Sometimes, Sylvain would coax Felix off his perch (never quite so aggressively as the first time, which Felix was thankful for, and was almost  _ kind _ on Sylvain’s part), and the unlikely pair would go floating out to sea, Felix straddled across the expanse of Sylvain’s rough stomach and Sylvain resting a large hand on Felix’s waist whenever a swell came by. Felix learned that Sylvain is  _ old. _ Mermaids, Sylvain once told him from underneath the pier, are like goldfish in that they simply keep growing. They start the size of a sea monkey, barely a pinprick of cells, and grow and grow and grow until they die. He learned that mermaids live and travel in groups much the way orcas do, and gathered that Sylvain is an outlier, a loner. Sylvain was not keen on indulging Felix about much of his past. Sure, he’d fill the air with tales of sunken ships brimming with gold and jewels aplenty, all more beautiful than Felix could ever imagine, or regale him with legends from the deep about wrecks that would’ve caught young, foolish mermaids when they still ruled the waves, but never did he elaborate on his own exploits. Felix knew it was not his place to pry (especially not when he was entirely at Sylvain’s mercy out on the deep blue sea), but sometimes Sylvain would slip up, add in a name or a place that would make Felix’s brow furrow ever-so-slightly, and the ghost of regret that passed through Sylvain’s amber eyes would make Felix wonder about the history carved into his skin. Eventually, what Felix put together was this: Sylvain is very old, he’d been excommunicated from his original family group (and if the still-healing gouges on his tail are anything to go by, the consequences of this are yet haunting him), and that maybe, just maybe, he likes spending time with Felix. Felix also learned that Sylvain is curious by nature and observant to a T, despite his flippant, frustratingly suave disposition. (Felix discovered that if one of Sylvian’s claws breaks off, the scales on that finger go too. He didn’t think very hard about that fact until one hand is stuffed in his mouth and he has three fingers buried deep, painting his stomach white when he realizes that those fantasies could become  _ real _ ). In turn, Felix revealed that he is the sole occupant of his father’s very large beach home, that he has a penchant for sailing, and that he never really learned how to swim. 

Their meetings continued like this for the better part of a month. Felix never pried about his end of the bargain, and Sylvain never seemed inclined to hold him to anything. They would talk, float, sometimes for hours on end before Sylvain would take Felix in his very large hands and set him on the dock before disappearing beneath the waves in a sunstroke flash, leaving Felix behind with a pressing problem between his legs and the ghost of  _ I’ll come when you need me, Kitten, _ looming over him like a heady cloud. 

One dreary afternoon, Felix found his feet carrying him to the edge of the peer. He did this, sometimes, where he would venture out to the sea when he needed to think about something. He found it calming. There was something about the gentle, rhythmic slosh of the green waves that cleared his mind and brought him back to zero. He’d received a letter from home- his father’s health was declining, and even though he still could recover, Glenn had asked for him to come back to help assess the situation and, if necessary, assist in getting affairs in order. A round-trip plane ticket for a flight that left in a week’s time had been carefully tucked between the folds of the letter. Felix knew this kind of call home was slated to happen at some point ever since he moved out to the shore. He did not want to make the decision of whether or not to go back. He did not want to think of the consequences either sides of that decision could have. Roderigue was far more stubborn than he was kind, but there was only so much that willpower can do against genetic disposition. The sun-bleached wood was slick, a sickly gray underneath the dreary, drizzling sky. He pulled a cigarette from the near-empty carton in his pocket and slipped it between his lips, dangling just far enough out that it could fall.  _ I guess bad habits do stick around, _ he thought dully. He drew a lighter, flicked it once, twice, and took a long drag. The smoke matched the cold clouds overhead. He took another lethargic inhale. 

The pier was long. His little Sunbeam was tied up about halfway out (he’d rather have ample space for other visitors at the sitting-end), the rest of it disappearing into the rainy midday mist. It seemed a good idea to him to go have his smoke out at the end. Maybe the cold of the water would clear his mind. His sandaled feet carried him forward into the fog, but something was off. Farther ahead, the wood was creaking like it was about to split, a woeful moan that Felix had only ever heard it make during a terrible storm. He forged ahead against his better judgement and did not acknowledge the thought of  _ if something happens to me here, I don’t have to go back home. _ The pier groaned. Felix picked up the pace. He wrinkled his nose- something smelled  _ off. _ There was an unusual metallic tang mixed in with damp wood and cigarette smoke, but it didn’t smell of blood. Dread oozed up into the pit of Felix’s stomach and turned his limbs to static. It didn’t smell of  _ human _ blood. 

There, at the end of the pier, was Sylvain, as Felix had never seen him. 

His top half was hauled up onto the wood, dumped there in a mirror of how Felix had woken up after their first encounter. Shallow breaths rattled through his ribcage. From what Felix could see, coming up behind him towards the crown of his head, his sun-kissed skin had taken on an awful pallor, and,  _ and-  _ Felix’s cigarette dripped from his lips. Blood was everywhere. Crimson and damning, it sat in great, fresh gashes across Sylvain’s chest, pooled around him and spilled between the pier’s planks to dye the ocean below a sickly brown. 

“ _ Sylvain! _ ” Felix cried. His voice ripped itself from his lungs, panicked and unrecognizable as he raced forward. “Sylvain,  _ what- _ ” The smell was overwhelming. Metallic and acrid, it turned dread to bile as Felix fell to his knees behind Sylvain and buried his hands in blood-red hair. It was sticky with more than just saltwater, and Felix’s throat filled with cotton. The fins of Sylvain’s ears had been ravaged. “Your earrings,” Felix breathed. There was a bite mark where three of them should be. Sylvain must have been attacked, caught off-guard by someone, some _ thing, _ with a vendetta. He knew that Sylvain had enemies, but to see the consequences firsthand… sat on solid wood, Felix was out of his depth. Sylvain’s eyes cracked open, amber and almost serpentine, and the smallest shreds of relief wrapped themselves around Felix. 

“Hey there, kitten. This must look pretty bad to you, huh?” Sylvain rumbled. Felix wanted to smack him. “Don’t worry, I’ll be just fine. Things like me recover quickly. I just needed somewhere to crash before heading home.” Felix wanted to protest, wanted to say  _ what do you fucking mean you’ll be fine, you’re bleeding out on the end of my pier, you stupid fish, _ but upon closer inspection, Sylvain was right. The blood on his chest had dried and coagulated to something that looked like the beginnings of a scab, and what Felix had thought to be a pool was really more of a haphazard splatter that must’ve come about when Sylvain was coming out of the ocean. Also, Felix was no authority on mer-biology, and he still wasn’t sure if he’d end up skewered if he spoke too much out of turn. Even he had the presence of mind to know that this was not the time to press that boundary. 

“Why are you here?” He asked instead, with only some of his usual bite. It was close enough, and if Sylvain couldn’t figure out what he really meant, even with all his many years behind him, then there wasn’t much Felix could do. Sylvain hummed. It sounded something inhuman. Felix watched as the smooth line of gills on Sylvain’s neck fluttered with it. Maybe it was closer to a trill. 

“I could ask the same of you.” Felix narrowed his eyes. Sylvain was a master of dodging questions. 

“I’ve been called back home,” He started. Maybe it wouldn’t hurt to confide. “My father is in poor health. My elder brother wants me to come home to organize affairs.” Felix snorted. “Wants me home so my father can rag on me for my uselessness one last time, more like.” Sylvain made another one of those strange little noises. It’d been so  _ long _ since Felix told anyone anything. “I was running from him the day you found me. I don’t even remember what he wanted, but he’d sent Glenn to come find me before he went home. He’d just finished chewing me out for abandoning the family ideals, or some stupid shit like that. The water is the one place Glenn won’t follow me.” Felix’s fingers flexed against Sylvain’s scalp. He’d moved- run, really- to the family beach house to shake the hold his family had on him. Sylvain held his attentive gaze on Felix. It spurred him onwards. “Glenn used to love the beach. His old room is full of all the books he used to fill his head with sea monster nonsense. He’d spend hours outside and then come back talking about all the friends he’d made, which is stupid, because we have a private beach. Nobody can get here without us knowing. I think he was just going crazy,” Felix huffed. 

“Although,” He said, staring forward and lost in his memory, “I think he did find something once. There was one time where he came back with a scale that we had never seen before. It looked like yours, but it was a dark blue. You had to hold a light to it to see that it wasn’t black. He stopped going to the water after that and never told us why. I think he said something about a Dimitri, but it doesn’t matter anymore.” 

Sylvain grit his teeth and slid into the sea, leaving Felix all alone. The blood on the pier had soaked irreparably into the wood.


	3. Chapter 3

**Summary for the Chapter:**

> porn :)

The next time Felix saw Sylvain, he was, once again, at the mercy of the ocean. He’d found himself caught on the water in a thunderstorm. Violent currents sent him careening off the side of his little Sunbeam, and the last thing he remembered was the horrible crack of the mast as it snapped, and an enormous wave crashed down over him. He tumbled through the sea, salt filling his eyes and nose and mouth and he couldn’t see, everything was so dark and he was being pushed and pulled this way and that and his sense of direction washed away with his sailboat. His lungs burned, he couldn’t  _ breathe, _ he swung and kicked and thrashed against the water but down, down he sank until the air left him and with the last of the bubbles went his consciousness. He didn’t see the flash of orange that swept him away. 

He woke with a start, coughing up sand and seawater. Everything hurt, felt wrong, like he’d had his skin pulled three inches from his skeleton and his insides rattled around. He rested on his hands and knees, just breathing, and let the world slowly, gently, filter back in. He felt solid ground beneath him, cold and smooth, a soft  _ plink-plink-plink _ filling his ears. His mouth tasted like he’d taken a big bite straight out of the shoreline, and a sharp, salty smell surrounded him. He was soaked to the bone, his hair a mangled mess, pallid and miserable. He blinked, hard, squeezing salt from his eyes, and waited for the smooth stone he was resting on to come into focus. Flaky mica particles gave it a gentle gleam. He looked up.

Felix was in a cavern. In front of him, a stone’s throw away, was a quiet pool, a tendril of which led back behind him into the darkness. Light from a lantern hastily suspended from a stalactite bounced off the water and onto the condensation that clung to every surface, reflecting in patterns like a kaleidoscope. He couldn’t look at it for too long- his head was still pounding. He gave himself a moment to let the vertigo pass and stood gently, wobbling like he was taking his first steps, and turned. The cave seemed to go back forever, but it was cluttered- things and  _ stuff _ were all over the floor, the ceiling, the walls. Jewelry crafted from the finest of precious metals hung from the hilts of ceremonial swords driven into the stone, interesting trinkets and tchotchkes sprinkled atop gorgeous fabrics and pieces of regalia, thick, ancient leather tomes with vellum pages laid carefully out to dry among them, alabaster boxes locked tight and chests thrown open to reveal their spoils, papers and parchments and scrolls of all kinds were  _ everywhere _ , immaculately cared for. Felix took a cautious step forward, as though if he were anything less than careful he ran the risk of being consumed by the cave, becoming nothing yet another curiosity himself.  _ Am I dreaming?  _ He reached a hand towards a bizarre spear laid purposefully away from everything else.

“Don’t touch that.”

Felix turned. Sylvain had pulled himself up onto the flat of a rock next to the crystalline pool at the front of the cave. Fractals of light bounced off of him, off of his tail, as though from the waist-down he was made of finned flame, all orange and red and gold, the colors reflecting onto the gemstones and metals all around. He was smiling, radiant. “I don’t know if I want you around all my sharp objects right after I saved you from drowning  _ again. _ ” He dropped something small and black on the gray stone-  _ my drybag! _ “I’m sorry to say this is the only thing I could salvage from your boat. The storm really did a number on it.” A ghost of something that looked to Felix like regret passed over Sylvain’s fine features. Felix wasn’t surprised to hear that his little Sunbeam hadn’t survived. “Come, Felix. Let me see you.” A nagging heat made itself known as Felix walked towards Sylvain’s outstretched hand, blooming across the tops of his thighs. Next to him, Felix was reminded of Sylvain’s sheer size. Even standing, he only came up to the muscled curve of Sylvain’s shoulder, eye-level with the top of a scar that stretched from the edge of his collarbone down across his broad chest. It was a milky white, matching the underside of the scale Felix had pulled from the pier, sleek and smooth, unlike the rest of him. Felix was close enough that if he reached out just a little, he could run the tips of his fingers along it and feel where the scar met the skin. Sylvain, as he was so fond of doing, took Felix’s chin in his hand and examined him the way one might look at a precious gem before setting it in something, and smiled approvingly. “I don’t know if you’ve noticed, but I’m fond of keeping my things in good shape.” He shifted back on the smooth rock, scales scratching against it, and pulled Felix into his lap, settling him just above where his skin became tail. Gently, so gently, he grasped Felix’s wrist and brought it to his lips to ghost a kiss over the scarlet band. Felix reckoned he was about the same color. “We’re bound together now, you know. I can’t have you putting yourself in danger like that.” Felix went hot all over. He knew he must’ve looked a fright, hair stuck to his shoulders and shirt in tatters and he must’ve been colder than he thought, because the places where Sylvain was touching him- his arm, his side, his back,  _ between his legs _ \- were starting to feel warm, tingly. Sylvain was looking at him like he was something to be cherished, held. The heat became more pressing. 

“Do you know what you want your end of the bargain to be?” Felix asked, voice rough from more than just the saltwater. He looked up, met Sylvain’s eyes. Sylvain  _ hmm _ ’d, trailing the point of a thumb carefully across Felix’s cheek. He’d be lying if he said he didn’t want to turn his head, nuzzle into the rough skin of Sylvain’s palm, take the end of a claw into his mouth and see if he cut himself on it. 

“I think,” Sylvain said, low and rumbling, “In exchange for saving you, twice now, kitten,” Felix felt his ears light up and decided that he really did not need that kind of distraction while hearing what he’d have to do as consequence of his dismal sense of self-preservation, “You’ll have to accept me as your protector, to keep you out of danger.” Sylvain smiled, small and earnest. The mark on his wrist  _ burned _ . “And, well. I think it’s only reasonable I teach you how to swim. What say you?” Felix pulled himself together. Sylvain was giving him an out, the option to say no, to reset the terms, but… Felix reached forward, allowing himself to feel the scars that wove across Sylvain’s chest, soft and smooth and ever-so-slightly shiny, and to feel the skin there, rough and demanding underneath his fingertips, rising and falling with Sylvain’s even, deep breaths. To have someone looking out for him couldn’t be all that bad, could it? It was nice, he realized, as his heart pounded and his cheeks pinkened, to be wanted. And, clearly, he should learn to swim. He cleared his throat. 

“I accept.” Sylvain grinned wide, flashing two rows of dangerous teeth (the texture of Sylvain’s skin suddenly became  _ very _ acute against Felix’s thighs). He leaned down, eye-to-eye with Felix, breath fanning over him and eyes trained on his lips. 

“Are you going to seal the deal, kitten?” Sylvain growled, and Felix, ever a man of action, lurched forward to catch Sylvain in a searing kiss. He arched his back as one of Sylvain’s hands smoothed down from the nape of his neck to his hips, scales catching on his shirt and Felix wanted to feel them, drink them in as they scraped shallow along bare skin. Sylvain tasted the way Felix thought he would, salt and sweat filling his senses, Sylvain moving to gently bite along Felix’s neck and shoulder. Felix gasped. His mouth fell open as he felt the sharp points dig in just so, the pressure narrowly eschewing drawing blood. “I was so glad I found you in time,” Sylvain growled, and Felix heard an  _ ah, _ tumble from his mouth as his cock twitched, “And I’m happy you’ve accepted my terms.” Sylvain leaned back, dragged his eyes over Felix- he looked  _ debauched _ , flushed, panting and sweaty, legs spread wide over Sylvain, bite marks blooming as he looked up from under dark lashes, hands pressed in front of him. Felix reached up, tangled his hands in Sylvain’s hair and pulled him back down. It was a little odd, he had to admit, kissing someone so much bigger than he was, but  _ fuck _ , the way Sylvain’s tongue slid out to lick his lips, pink and long and tapered, set him on fire. Those rushed, hurried nights with nothing but his imagination and his hand could never have prepared him for the real thing. He moaned against Sylvain, rolled his hips forward so he could feel the hard plane of Sylvain’s abs against his cock through the thin, damp fabric of his shorts, a whine rising high in his throat- “Oh? Excited, kitten?” Felix had half a mind to put a ban on that pet name, but when he opened his mouth to bite back nothing but a breathy keen came out.  _ Yes,  _ he was excited, he had the object of his imagination in front of him, kissing him back,  _ wanting him too _ . “You’ll have to tell me exactly what you want, then.”

“Tease,” growled Felix, grinding down; a bead of precum rolled down the shaft of his cock, forcing a sharp breath from him. Two could play that game. Sylvain, a creature of habit, moved to take Felix’s face in his hand, but Felix instead guided it to his mouth and opened up to take in the sharp end of a finger, as wide around as three of his own. It tasted as the rest of him did, like salt and sand and sweat, and Felix tentatively swiped his tongue over the tip- it was smooth, rounded. 

“That’s twice now I’ve had to bite off one of my claws for you, you know.” Sylvain’s eyes narrowed. He slid the finger in and out, letting it become slick with spit, petting along Felix’s velveteen tongue. The scales there, thin and closely cropped to Sylvain’s rough skin, scraped along the inside of Felix’s mouth, leaving the faintest copper tang in their wake. Felix took it in as best he could, hollowing his cheeks and sucking and wondering idly what would become of his throat were one of those brilliant scales to come loose and fly down the soft tissue of his windpipe. He shivered, sighed around the finger as saliva made its way between his pinkened lips and down his chin. The webbing on Sylvain’s hand scraped along his cheek every time he took the finger deeper, down to the first knuckle. It bumped along the back of his throat. Sylvain’s other hand came up to smooth across Felix’s neck, as though to coax it into taking his finger farther down, and it set Felix on  _ fire. _ He felt so small, so helpless, entirely at Sylvain’s mercy and he loved it. “Oh, kitten. You’re so eager.” His lazy grin adopted a sharp edge, and he pressed ever so lightly on Felix’s neck. “You still have to tell me what you want, though.” A million possibilities flew through Felix’s head. Hands, mouth, teeth, tongue; he wanted any of them, all of them. “Unless you need me to do that for you too? Do you need me to tell you how I want you?” Sylvain gently pulled his spit-slick finger from Felix’s mouth, wiping it across his cheek and leaving a shiny trail in its wake. God, Felix was already so far in his own head- he just nodded. Any decision-making ability had flown out of his head the moment Sylvain had pressed down on his neck. 

“I don’t know if you’ll be ready to take my cocks for a while yet, kitten.”  _ Cocks? _ Plural? Felix blanked out for a moment, lost in his imagination. Of course Sylvain had two, he was a  _ shark, _ for crying out loud. God, they’d fill him up so well, stuff him full until he split in half- “Oh? Like that idea, do you?” Sylvain caught the edge of Felix’s soaked (and not just by saltwater, not anymore) shorts on a claw, teasing at the thin fabric. It split around the sharp point. “Well, we’ll just have to work up to it, then. I’d love nothing more than to get them in you, but,” he sighed, feigning woe, “I already told you that I take care of my things.” A deafening  _ rip _ echoed through the cave as Sylvain, quite literally, shredded Felix’s shorts. They fell in ribbons to the smooth, sparkly cave floor. His cock immediately rubbed up against Sylvain’s rough skin, and Felix  _ moaned, _ wanton and unbidden in a way he’d never experienced. The sensation ripped through him, pulled generous beads of precum from the pink, flushed head, and it was a miracle that he didn’t spend right there. Sylvain laughed, low and rumbly, and then Felix was in the air, and then Sylvain held him  _ right above his face. _ “Let’s start with this, hm?” 

Sylvain’s tongue teased at Felix’s hole. It was warm and wet and  _ dexterous, _ tapered to a point but, as Felix soon learned, it flared out considerably. He shook as it pushed into him, less intent on opening him up (Sylvain’s promise of  _ later _ bounced around Felix’s head like a prayer) and more focused on bringing him pleasure. He was so worked up by  _ Sylvain _ that he spent embarrassingly quickly, shaking apart with a moan that ripped from his throat as Sylvain’s tongue pressed hard into his prostate. 

“There you go, kitten.” Sylvain growled. “All mine.”

**Notes for the Chapter:**

> thank you so much for reading!

**Author's Note:**

> mmm, eleventh hour mermay. thank you for reading! big huge giant mondo meat thanks to my boy flo ([twitter](https://twitter.com/thisvibeisdead) [ao3](https://archiveofourown.org/users/thevibeisdead)) for being my lovely beta from an entirely different time zone and ever so patiently listening to me whine as this went though about seven different iterations.


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